[gnome-tetravex] Fix drawing code, part 2.

[Arnaud B. <arnaudb src gnome org>]

commit 4cec1edbba1d0919244294a43a9a707a561e87ad
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Wed Sep 18 04:40:47 2019 +0200

    Fix drawing code, part 2.
    
    Redraw the last selected tile,
    fixing the drawing bug of when
    inverting two contiguous tiles
    multiple times. Not sure it is
    a good idea to search a better
    way of doing that, so pushing.

 src/puzzle-view.vala | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
---
diff --git a/src/puzzle-view.vala b/src/puzzle-view.vala
index d11a8fd..fe8c417 100644
--- a/src/puzzle-view.vala
+++ b/src/puzzle-view.vala
@@ -80,6 +80,7 @@ private class PuzzleView : Gtk.DrawingArea
 
     /* Tile being controlled by the mouse */
     private TileImage? selected_tile = null;
+    private TileImage? last_selected_tile = null;
     internal signal void tile_selected (bool selected);
 
     /* Timeout to detect if a click is a selection or a drag */
@@ -355,6 +356,19 @@ private class PuzzleView : Gtk.DrawingArea
             context.restore ();
         }
 
+        /* Redraw last selected tile, fixing problem when interverting multiple times two contiguous tiles */
+        if ((selected_tile == null)
+         && (last_selected_tile != null))
+        {
+            context.save ();
+            context.translate ((int) (((!) last_selected_tile).x + 0.5), (int) (((!) last_selected_tile).y + 
0.5));
+            if (puzzle.paused)
+                theme.draw_paused_tile (context, size);
+            else
+                theme.draw_tile (context, size, ((!) last_selected_tile).tile);
+            context.restore ();
+        }
+
         /* Draw pause overlay */
         if (puzzle.paused)
         {
@@ -398,6 +412,7 @@ private class PuzzleView : Gtk.DrawingArea
             if (x >= image.x && x <= image.x + size && y >= image.y && y <= image.y + size)
             {
                 selected_tile = image;
+                last_selected_tile = image;
                 tile_selected (true);
                 selected_x_offset = x - image.x;
                 selected_y_offset = y - image.y;